As in adults, the etiology of childhood IBS is multi-factorial, with food intolerance and increased gastrointestinal inflammation being potential factors. Another factor, that of malabsorption of fermentable substrates (e.g., fructose), has frequently been postulated as a form of food intolerance that exacerbates IBS symptoms in adults and children. Studies suggest up to 61% of children with RAP have fructose malabsorption. The interactions between factors such as increased gastrointestinal inflammation and malabsorption of fermentable substrates and they relate to an individual patient is currently unknown.